U.S. patent application number 16/178379 was filed with the patent office on 2019-05-23 for organ restraint coverings and coatings for atrial fibrillation prevention.
The applicant listed for this patent is Edwards Lifesciences Corporation. Invention is credited to Stanton J. Rowe, Robert S. Schwartz.
Application Number | 20190151524 16/178379 |
Document ID | / |
Family ID | 66534137 |
Filed Date | 2019-05-23 |
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United States Patent
Application |
20190151524 |
Kind Code |
A1 |
Rowe; Stanton J. ; et
al. |
May 23, 2019 |
ORGAN RESTRAINT COVERINGS AND COATINGS FOR ATRIAL FIBRILLATION
PREVENTION
Abstract
A method of restraining expansion of an atrium of a heart
involves accessing a heart of a patient, applying a coating over at
least a portion of a surface of an atrium of the heart, and at
least partially curing the coating to increase the rigidity
thereof. Atrial fibrillation prevention.
Inventors: |
Rowe; Stanton J.; (Newport
Coast, CA) ; Schwartz; Robert S.; (Inver Grove
Heights, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Edwards Lifesciences Corporation |
Irvine |
CA |
US |
|
|
Family ID: |
66534137 |
Appl. No.: |
16/178379 |
Filed: |
November 1, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62587995 |
Nov 17, 2017 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61L 31/146 20130101;
A61M 1/125 20140204; A61L 31/148 20130101; A61M 1/122 20140204;
A61M 1/1008 20140204; A61F 2/2481 20130101; A61F 7/10 20130101 |
International
Class: |
A61M 1/12 20060101
A61M001/12; A61M 1/10 20060101 A61M001/10; A61F 2/24 20060101
A61F002/24 |
Claims
1. A method of restraining expansion of an atrium of a heart, the
method comprising: accessing a heart of a patient; applying a
coating over at least a portion of a surface of an atrium of the
heart; and at least partially curing the coating to increase
rigidity thereof.
2. The method of claim 1, wherein the coating comprises
bio-resorbable material.
3. The method of claim 1, wherein said applying the coating and
said at least partially curing the coating at least partially limit
stretching of the atrium.
4. The method of claim 1, wherein said applying the coating and
said at least partially curing the coating at least partially
increase elasticity associated with a wall of the atrium.
5. The method of claim 1, wherein said applying the coating
comprises brushing the coating onto the surface of the atrium.
6. The method of claim 1, wherein said applying the coating
comprises spraying the coating onto the surface of the atrium.
7. The method of claim 1, wherein said applying the coating
comprises expelling the coating from an applicator tip of a
syringe.
8. The method of claim 1, wherein the coating has adhesive
properties.
9. The method of claim 1, wherein the coating comprises
collagen.
10. The method of claim 1, wherein the coating comprises
hydrophobic polymer.
11. The method of claim 1, wherein the coating comprises polymer
doped with carbon nanotubes.
12. The method of claim 1, wherein the coating comprises oxidized
dextran.
13. The method of claim 1, wherein said at least partially curing
the coating comprises exposing the coating to light.
14. The method of claim 13, wherein the light is ultraviolet (UV)
light.
15. The method of claim 1, wherein the coating is configured to
change color as it cures to provide a visual indication of
curing.
16. The method of claim 1, wherein the coating has a Young's
modulus of elasticity of between 0.2 MPa and 1.0 MPa when
cured.
17. The method of claim 1, wherein the coating is configured such
that, when cured, a surface of the coating does not adhere to
biological tissue coming in contact therewith.
18. A method of restraining expansion of an atrium of a heart, the
method comprising: accessing a heart of a patient; and disposing a
biocompatible covering over at least a portion of a surface of an
atrium of the heart; wherein the biocompatible covering is
configured to at least partially restrain outward expansion of the
surface of the atrium.
19. The method of claim 18, wherein the biocompatible covering is
bio-resorbable.
20. The method of claim 18, wherein the biocompatible covering
comprises a mesh patch.
21. The method of claim 18, wherein the biocompatible covering has
a Young's modulus of elasticity of between 0.2 MPa and 1.0 MPa.
22. The method of claim 18, further comprising trimming the
biocompatible covering to fit the surface of the atrium after said
disposing the biocompatible covering.
23. The method of claim 18, further comprising suturing the
biocompatible covering to the heart.
24. The method of claim 18, further comprising: applying adhesive
to one or more of the surface of the atrium and the biocompatible
covering; and adhering the biocompatible covering to the surface of
the atrium using the adhesive.
25. An atrial restraint covering comprising: a form of
biocompatible material shaped to cover a surface of an atrium of a
heart; wherein the form of biocompatible material is configured to
be secured to the surface of the atrium and at least partially
restrict outward expansion thereof.
26. The atrial restraint covering of claim 25, wherein the form of
biocompatible material is bio-resorbable.
27. The atrial restraint covering of claim 25, wherein the form of
biocompatible material comprises a mesh patch.
28. The atrial restraint covering of claim 25, wherein the form of
biocompatible material has a Young's modulus of elasticity of
between 0.2 MPa and 1.0 MPa.
29. The atrial restraint covering of claim 25, wherein the form of
biocompatible material comprises adhesive to adhering to the
surface of the atrium.
Description
RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 62/587,995, filed Nov. 17, 2017, and entitled ORGAN
RESTRAINT COVERINGS AND COATINGS FOR ATRIAL FIBRILLATION
PREVENTION, the disclosure of which is hereby incorporated by
reference in its entirety.
BACKGROUND
Field
[0002] The present disclosure generally relates to the field of
vascular surgery, such as cardiac surgery.
Description of Related Art
[0003] Patients of cardiac surgery and other vascular operations
can develop atrial fibrillation post-operatively due to various
conditions and/or factors. Atrial fibrillation is associated with
certain health complications, including increased patient
mortality, and therefore prevention and/or treatment of atrial
fibrillation during surgery and/or post-operatively can improve
patient health.
SUMMARY
[0004] In some implementations, the present disclosure relates to a
method of restraining expansion of an atrium of a heart. The method
comprises accessing a heart of a patient, applying a coating over
at least a portion of a surface of an atrium of the heart, and at
least partially curing the coating to increase rigidity
thereof.
[0005] The coating may comprise bio-resorbable material. In certain
embodiments, applying the coating and at least partially curing the
coating at least partially limit stretching of the atrium. In
certain embodiments, applying the coating and at least partially
curing the coating at least partially increase elasticity
associated with a wall of the atrium. In certain embodiments,
applying the coating and at least partially curing the coating at
least partially decrease elasticity associated with a wall of the
atrium. In certain embodiments, applying the coating comprises
brushing the coating onto the surface of the atrium. In certain
embodiments, applying the coating comprises spraying the coating
onto the surface of the atrium. In certain embodiments, applying
the coating comprises expelling the coating from an applicator tip
of a syringe.
[0006] The coating may have adhesive properties. In certain
embodiments, the coating comprises collagen. In certain
embodiments, the coating comprises hydrophobic polymer. In certain
embodiments, the coating comprises polymer doped with carbon
nanotubes. In certain embodiments, the coating comprises oxidized
dextran.
[0007] In certain embodiments, at least partially curing the
coating comprises exposing the coating to light. For example, the
light may be ultraviolet (UV) light. The coating may be configured
to change color as it cures to provide a visual indication of
curing. In certain embodiments, the coating has a Young's modulus
of elasticity of between 0.2 MPa and 1.0 MPa when cured. The
coating may be configured such that, when cured, a surface of the
coating does not adhere to biological tissue coming in contact
therewith.
[0008] In some implementations, the present disclosure relates to a
method of restraining expansion of an atrium of a heart. The method
comprises accessing a heart of a patient, and disposing a
biocompatible covering over at least a portion of a surface of an
atrium of the heart. The biocompatible covering is configured to at
least partially restrain outward expansion of the surface of the
atrium.
[0009] The biocompatible covering may advantageously be
bio-resorbable. In certain embodiments, the biocompatible covering
comprises a mesh patch. The biocompatible covering may have a
Young's modulus of elasticity of between 0.2 MPa and 1.0 MPa. In
certain embodiments, the method further comprises trimming the
biocompatible covering to fit the surface of the atrium disposing
the biocompatible covering. The method may further comprise
suturing the biocompatible covering to the heart. In certain
embodiments, the method further comprises applying adhesive to one
or more of the surface of the atrium and the biocompatible
covering, and adhering the biocompatible covering to the surface of
the atrium using the adhesive.
[0010] In some implementations, the present disclosure relates to
an atrial restraint covering comprising a form of biocompatible
material shaped to cover a surface of an atrium of a heart, wherein
the form of biocompatible material is configured to be secured to
the surface of the atrium and at least partially restrict outward
expansion thereof.
[0011] The form of biocompatible material may be bio-resorbable. In
certain embodiments, the form of biocompatible material comprises a
mesh patch. In certain embodiments, the form of biocompatible
material has a Young's modulus of elasticity of between 0.2 MPa and
1.0 MPa. In certain embodiments, the form of biocompatible material
comprises adhesive to adhering to the surface of the atrium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Various embodiments are depicted in the accompanying
drawings for illustrative purposes, and should in no way be
interpreted as limiting the scope of the inventions. In addition,
various features of different disclosed embodiments can be combined
to form additional embodiments, which are part of this disclosure.
Throughout the drawings, reference numbers may be reused to
indicate correspondence between reference elements.
[0013] FIG. 1 provides an example cross-sectional view of a human
heart.
[0014] FIG. 2 illustrates an example cross-sectional representation
of a heart experiencing atrial fibrillation.
[0015] FIGS. 3 and 4 show anterior and posterior views,
respectively, of a human heart.
[0016] FIGS. 5 and 6 illustrates anterior and posterior views,
respectively, of a heart having an atrial restraint coating or
covering applied to one or more atria thereof in accordance with
one or more embodiments.
DETAILED DESCRIPTION
[0017] The headings provided herein are for convenience only and do
not necessarily affect the scope or meaning of the claimed
invention.
[0018] Although certain preferred embodiments and examples are
disclosed below, inventive subject matter extends beyond the
specifically disclosed embodiments to other alternative embodiments
and/or uses and to modifications and equivalents thereof. Thus, the
scope of the claims that may arise herefrom is not limited by any
of the particular embodiments described below. For example, in any
method or process disclosed herein, the acts or operations of the
method or process may be performed in any suitable sequence and are
not necessarily limited to any particular disclosed sequence.
Various operations may be described as multiple discrete operations
in turn, in a manner that may be helpful in understanding certain
embodiments; however, the order of description should not be
construed to imply that these operations are order dependent.
Additionally, the structures, systems, and/or devices described
herein may be embodied as integrated components or as separate
components. For purposes of comparing various embodiments, certain
aspects and advantages of these embodiments are described. Not
necessarily all such aspects or advantages are achieved by any
particular embodiment. Thus, for example, various embodiments may
be carried out in a manner that achieves or optimizes one advantage
or group of advantages as taught herein without necessarily
achieving other aspects or advantages as may also be taught or
suggested herein.
Terminology
[0019] Certain standard anatomical terms of location are used
herein to refer to the anatomy of animals, and namely humans, with
respect to the preferred embodiments. Although certain spatially
relative terms, such as "outer," "inner," "upper," "lower,"
"below," "above," "vertical," "horizontal," "top," "bottom," and
similar terms, are used herein to describe a spatial relationship
of one device/element or anatomical structure to another
device/element or anatomical structure, it is understood that these
terms are used herein for ease of description to describe the
positional relationship between element(s)/structures(s), as
illustrated in the drawings. Spatially relative terms are intended
to encompass different orientations of the
element(s)/structures(s), in use or operation, in addition to the
orientations depicted in the drawings. For example, an
element/structure described as "above" another element/structure
may represent a position that is below or beside such other
element/structure with respect to alternate orientations of the
subject patient or element/structure, and vice-versa.
[0020] Furthermore, references may be made herein to certain
anatomical planes, such as the sagittal plane, or median plane, or
longitudinal plane, referring to a plane parallel to the sagittal
suture, and/or other sagittal planes (i.e., parasagittal planes)
parallel thereto. In addition, "frontal plane," or "coronal plane,"
may refer to an X-Y plane that is perpendicular to the ground when
standing, which divides the body into back and front, or posterior
and anterior, portions. Furthermore, a "transverse plane," or
"cross-sectional plane," or horizontal plane, may refer to an X-Z
plane that is parallel to the ground when standing, that divides
the body in upper and lower portions, such as superior and
inferior. A "longitudinal plane" may refer to any plane
perpendicular to the transverse plane. Furthermore, various axes
may be described, such as a longitudinal axis, which may refer to
an axis that is directed towards head of a human in the cranial
direction and/or directed towards inferior of a human in caudal
direction. A left-right or horizontal axis, which may refer to an
axis that is directed towards the left-hand side and/or right-hand
side of a patient. An anteroposterior axis which may refer to an
axis that is directed towards the belly of a human in the anterior
direction and/or directed towards the back of a human in the
posterior direction.
Overview
[0021] In humans and other vertebrate animals, the heart generally
comprises a muscular organ having four pumping chambers, wherein
the flow thereof is at least partially controlled by various heart
valves, namely, the aortic, mitral (or bicuspid), tricuspid, and
pulmonary valves. The valves may be configured to open and close in
response to a pressure gradient present during various stages of
the cardiac cycle (e.g., relaxation and contraction) to at least
partially control the flow of blood to a respective region of the
heart and/or to blood vessels (e.g., pulmonary, aorta, etc.). The
contraction of the various heart muscles may be prompted by signals
generated by the electrical system of the heart, which is discussed
in detail below.
[0022] FIG. 1 illustrates an example representation of a heart 1
having various features relevant to certain embodiments of the
present inventive disclosure. The heart 1 includes four chambers,
namely the left atrium 2, the left ventricle 3, the right ventricle
4, and the right atrium 5. A wall of muscle 17, referred to as the
septum, separates the left 2 and right 5 atria and the left 3 and
right 4 ventricles. The heart 1 further includes four valves for
aiding the circulation of blood therein, including the tricuspid
valve 8, which separates the right atrium 5 from the right
ventricle 4. The tricuspid valve 8 may generally have three cusps
or leaflets and may generally close during ventricular contraction
(i.e., systole) and open during ventricular expansion (i.e.,
diastole). The valves of the heart 1 further include the pulmonary
valve 9, which separates the right ventricle 4 from the pulmonary
artery 11, and may be configured to open during systole so that
blood may be pumped toward the lungs, and close during diastole to
prevent blood from leaking back into the heart from the pulmonary
artery. The pulmonary valve 9 generally has three cusps/leaflets,
wherein each one may have a crescent-type shape. The heart 1
further includes the mitral valve 6, which generally has two
cusps/leaflets and separates the left atrium 2 from the left
ventricle 3. The mitral valve 6 may generally be configured to open
during diastole so that blood in the left atrium 2 can flow into
the left ventricle 3, and advantageously close during diastole to
prevent blood from leaking back into the left atrium 2. The aortic
valve 7 separates the left ventricle 3 from the aorta 12. The
aortic valve 7 is configured to open during systole to allow blood
leaving the left ventricle 3 to enter the aorta 12, and close
during diastole to prevent blood from leaking back into the left
ventricle 3.
[0023] Heart valves may generally comprise a relatively dense
fibrous ring, referred to herein as the annulus, as well as a
plurality of leaflets or cusps attached to the annulus. Generally,
the size and position of the leaflets or cusps may be such that
when the heart contracts, the resulting increased blood pressure
produced within the corresponding heart chamber forces the leaflets
at least partially open to allow flow from the heart chamber. As
the pressure in the heart chamber subsides, the pressure in the
subsequent chamber or blood vessel may become dominant and press
back against the leaflets. As a result, the leaflets/cusps come in
apposition to each other, thereby closing the flow passage.
[0024] The atrioventricular (i.e., mitral and tricuspid) heart
valves may further comprise a collection of chordae tendineae (16,
18) and papillary muscles (10, 15) for securing the leaflets of the
respective valves to promote and/or facilitate proper coaptation of
the valve leaflets and prevent prolapse thereof. The papillary
muscles (10, 15), for example, may generally comprise finger-like
projections from the ventricle wall. With respect to the mitral
valve 6, a normal mitral valve may comprise two leaflets (anterior
and posterior) and two corresponding papillary muscles 15. When the
left ventricle 3 contracts, the intraventricular pressure forces
the valve to close, while the chordae tendineae 16 keep the
leaflets coapting together and prevent the valve from opening in
the wrong direction, thereby preventing blood to flow back to the
left atrium 2. With respect to the tricuspid valve 8, the normal
tricuspid valve may comprise three leaflets (two shown in FIG. 1)
and three corresponding papillary muscles 10 (two shown in FIG. 1).
The leaflets of the tricuspid valve may be referred to as the
anterior, posterior and septal leaflets, respectively. The valve
leaflets are connected to the papillary muscles by the chordae
tendineae 18, which are disposed in the right ventricle 4 along
with the papillary muscles 10. The right ventricular papillary
muscles 10 originate in the right ventricle wall, and attach to the
anterior, posterior and septal leaflets of the tricuspid valve,
respectively, via the chordae tendineae 18.
Cardiac Electrical System
[0025] The electrical system of the heart generally controls the
events associated with the pumping of blood by the heart. With
further reference to FIG. 1, the heart 1 comprises different types
of cells, namely cardiac muscle cells (also known as cardiomyocytes
or myocardiocytes) and cardiac pacemaker cells. For example, the
atria (2, 5) and ventricles (3, 4) comprise cardiomyocytes, which
are the muscle cells that make up the cardiac muscle. The cardiac
muscle cells are generally configured to shorten and lengthen their
fibers and provide desirable elasticity to allow for stretching.
Each myocardial cell contains myofibrils, which are specialized
organelles consisting of long chains of sarcomeres, the fundamental
contractile units of muscle cells.
[0026] The electrical system of the heart utilizes the cardiac
pacemaker cells, which are generally configured to carry electrical
impulses that drive the beating of the heart 1. The cardiac
pacemaker cells serve to generate and send out electrical impulses,
and to transfer electrical impulses cell-to-cell along electrical
conduction paths. The cardiac pacemaker cells further may also
receive and respond to electrical impulses from the brain. The
cells of the heart are connected by cellular bridges, which
comprise relatively porous junctions called intercalated discs that
form junctions between the cells. The cellular bridges permit
sodium, potassium and calcium to easily diffuse from cell-to-cell,
allowing for depolarization and repolarization in the myocardium
such that the heart muscle can act as a single coordinated
unit.
[0027] The electrical system of the heart comprises the sinoatrial
(SA) node 21, which is located in the right atrium 5 of the heart
1, the atrioventricular (AV) node 22, which is located on the
interatrial septum in proximity to the tricuspid valve 8, and the
His-Purkinje system 23, which is located along the walls of the
left 3 and right 4 ventricles.
[0028] A heartbeat represents a single cycle in which the heart's
chambers relax and contract to pump blood. As described above, this
cycle includes the opening and closing of the inlet and outlet
valves of the right and left ventricles of the heart. Each beat of
the heart is generally set in motion by an electrical signal
generated and propagated by the heart's electrical system. In a
normal, healthy heart, each beat begins with a signal from the SA
node 21. This signal is generated as the vena cavae (19, 29) fill
the right atrium 5 with blood, and spreads across the cells of the
right 5 and left 2 atria. The flow of electrical signals is
represented by the illustrated shaded arrows in FIG. 1. The
electrical signal from the SA node 21 causes the atria to contract,
which pushes blood through the open mitral 6 and tricuspid 8 valves
from the atria into the left 3 and right 4 ventricles,
respectively.
[0029] The electrical signal arrives at the AV node 22 near the
ventricles, where it may slow for an instant to allow the right 4
and left 3 ventricles to fill with blood. The signal is then
released and moves along a pathway called the bundle of His 24,
which is located in the walls of the ventricles. From the bundle of
His 24, the signal fibers divide into left 26 and right 25 bundle
branches through the Purkinje fibers 23. These fibers connect
directly to the cells in the walls of the left 3 and right 4
ventricles. The electrical signal spreads across the cells of the
ventricle walls, causing both ventricles to contract. Generally,
the left ventricle may contract an instant before the right
ventricle. Contraction of the right ventricle 4 pushes blood
through the pulmonary valve 9 to the lungs (not shown), while
contraction of the left ventricle 3 pushes blood through the aortic
valve 6 to the rest of the body. As the electrical signal passes,
the walls of the ventricles relax and await the next signal.
Atrial Fibrillation
[0030] FIG. 1, as described above, illustrates a normal electrical
flow, resulting in a regular heart rhythm that may be associated
with a generally healthy heart. However, in certain patients or
individuals, various conditions and/or events can result in
compromised electrical flow, causing the development and/or
occurrence of an abnormal heart rhythm. For example, atrial
fibrillation is a condition associated with abnormal electrical
flow and/or heart rhythm characterized by relatively rapid and
irregular beating of the atria.
[0031] FIG. 2 illustrates an example cross-sectional representation
of the heart 1 of FIG. 1 experiencing atrial fibrillation. When
atrial fibrillation occurs, the normal regular electrical impulses
generated by the sinoatrial (SA) node 21 in the right atrium 5 may
become overwhelmed by disorganized electrical impulses, which may
lead to irregular conduction of ventricular impulses that generate
the heartbeat. The illustrated shaded arrows represent the erratic
electrical impulses that can be associated with atrial
fibrillation. Atrial fibrillation generally originates in the right
atrium 5, that where conduction path disturbances begin.
[0032] Various pathologic developments can lead to, or be
associated with, atrial fibrillation. For example, progressive
fibrosis of the atria may contribute at least in part to atrial
fibrillation. The formation of fibrous tissue associated with
fibrosis can disrupt or otherwise affect the electrical pathways of
the cardiac electrical system due to interstitial expansion
associated with tissue fibrosis. In addition to fibrosis in the
muscle mass of the atria, fibrosis may also occur in the sinoatrial
node 21 and/or atrioventricular node 22, which may lead to atrial
fibrillation.
[0033] Fibrosis of the atria may be due to atrial dilation, or
stretch, in some cases. Dilation of the atria can be due to a rise
in the pressure within the heart, which may be caused by fluid
overload, or may be due to a structural abnormality in the heart,
such as valvular heart disease (e.g., mitral stenosis, mitral
regurgitation, tricuspid regurgitation), hypertension, congestive
heart failure, or other condition. Dilation of the atria can lead
to the activation of the renin aldosterone angiotensin system
(RAAS), and subsequent increase in matrix metalloproteinases and
disintegrin, which can lead to atrial remodeling and fibrosis
and/or loss of atrial muscle mass.
[0034] In addition to atrial dilation, inflammation in the heart
can cause fibrosis of the atria. For example, inflammation may be
due to injury associated with a cardiac surgery, such as a valve
repair operation, or the like. Alternatively, inflammation may be
caused by sarcoidosis, autoimmune disorders, or other condition.
Other cardiovascular factors that may be associated with the
development of atrial fibrillation include high blood pressure,
coronary artery disease, mitral stenosis (e.g., due to rheumatic
heart disease or mitral valve prolapse), mitral regurgitation,
hypertrophic cardiomyopathy (HCM), pericarditis, and congenital
heart disease. Additionally, lung diseases (such as pneumonia, lung
cancer, pulmonary embolism, and sarcoidosis) may contribute to the
development of atrial fibrillation in some patients.
Development of Post-Operative Atrial Fibrillation
[0035] In addition to the various physiological conditions
described above that may contribute to atrial fibrillation, in some
situations, atrial fibrillation may be developed in connection with
a vascular operation, such post-operatively in the days following a
vascular operation. Various factors may bear on the likelihood of a
patient developing post-operative atrial fibrillation, such as age,
medical history (e.g., history of atrial fibrillation, chronic
obstructive pulmonary disease (COPD)), concurrent valve surgery,
withdrawal of post-operative treatment (e.g., beta-adrenergic
blocking agents (i.e., beta blocker), angiotensin converting enzyme
inhibitors (ACE inhibitor)), beta-blocker treatment (e.g.,
pre-operative and/or post-operative), ACE inhibitor treatment
(e.g., pre-operative and/or post-operative), and/or other factors.
Generally, for patients that experience post-operative atrial
fibrillation, the onset of atrial fibrillation may occur
approximately 2-3 days after surgery.
[0036] Atrial dilation/stretching may be considered a primary
variable associated with post-operative atrial fibrillation. In
some situations, occurrence of post-operative atrial fibrillation
may follow, at least in part, the following progression: First, the
patient undergoes a surgical procedure, such as a vascular surgical
operation (e.g., cardiac surgery). In connection with the
operation, the patient may be subject to drug and/or fluid
management. For example, the patient may receive post-surgery
intravenous (IV) fluid loading and/or diuretic/drug volume
management. Such treatment may result in fluid overload, which may
lead to atrial stretching due to increased pressure in one or more
atria. Atrial stretching may occur over a 1-2-day period, or
longer, resulting in dilation of one or both of the atria. Fibrotic
atrial tissue may form in connection with atrial stretching. Atrial
stretching and/or fibrotic atrial tissue formation may result in an
increased incidence of post-operative atrial fibrillation (e.g.,
30-40% increased incidence of post-operative atrial fibrillation).
In addition, inflammation associated with surgical operations can
contribute the onset of post-operative atrial fibrillation, and
reduced inflammation may generally correlate to a reduced risk of
atrial fibrillation.
[0037] Post-operative atrial fibrillation is generally associated
with increased patient morbidity, as well as economic burden. For
example, post-operative atrial fibrillation is generally associated
with increased incidence of congestive heart failure, increased
hemodynamic instability, increase renal insufficiency, increased
repeat hospitalizations, increased risk of stroke, and increase in
hospital mortality and 6-month mortality. Post-operative atrial
fibrillation also represents a systemic burden, wherein intensive
care unit (ICU) stay, hospital length of stay, hospital charges,
and rates of discharge to extended care facilities are increased as
a result of post-operative atrial fibrillation.
[0038] Furthermore, because an initial incidence of atrial
fibrillation generally results in recurring, progressively more
severe, episodes of atrial fibrillation in a patient, the
consequences of allowing atrial fibrillation to develop
post-operatively can be considered particularly severe for a given
patient. For example, a given patient may initially experience
intermittent/sporadic episodes of atrial fibrillation as a result
of post-operative atrial dilation and/or inflammation, with
recurring episodes progressively increasing in frequency and/or
severity.
Prevention of Post-Operative Atrial Stretch and Inflammation
[0039] The development of atrial fibrillation post-operatively can
have a serious negative impact on patient quality of life. As
discussed above, atrial stretch and inflammation may represent root
causes of post-operative atrial fibrillation in some situations.
Therefore, by reducing or restricting atrial stretch and/or
inflammation during vascular surgery, or over a period of time
thereafter, incidences of post-operative atrial fibrillation can be
reduced. The majority of post-operative atrial fibrillation
instances may occur within the first two days after surgery, and
therefore, prevention of post-operative atrial stretch and/or
inflammation may be particularly significant during the initial
days after surgery.
[0040] Generally, atrial diameter expansion of greater than 5 mm
may be correlated with chronic atrial fibrillation in some cases.
Furthermore, increase in atrial circumference of greater than 10%,
and/or increase in atrial volume of greater than 8.5 mL may be
associated with chronic atrial fibrillation. Therefore, embodiments
disclosed herein may be designed to limit or restrict atrial
stretch to prevent expansion of atrial diameter by 5 mm or more,
increase in circumferential stretch by greater than 10%, and/or
increase in atrial volume by 8.5 mL or more in order to reduce
incidences of atrial fibrillation. With regard to fluid overload,
in some situations, the introduction of around 1.5 additional
liters of fluid to a patient's vascular system may be correlated
with increased rates of atrial fibrillation. Generally, the greater
the amount of fluid added, the greater the amount of atrial stress
that may be experienced by the patient.
[0041] In some implementations, the present disclosure provides a
means for restricting atrial stretching in either or both of the
left and right atria, and/or the reduction of inflammation
associated with the atria, for a post-operative period after a
surgical procedure, thereby reducing the likelihood of onset of
post-operative atrial fibrillation. For example, embodiments
disclosed herein may be suitable for restricting atrial stretching
and/or reducing inflammation for a period of up to five days after
a surgical procedure. In some implementations, a post-operative
atrial fibrillation prevention device may be implanted or applied
at the time of surgery, but may advantageously be removed at a
later time. For example, in some embodiments, an atrial
fibrillation prevention device may be removed at or about the time
that chest drainage tubes associated with a surgical operation are
removed, which may correspond with a time period approximately five
days after completion of the surgery, or other time period.
Atrial Restraint Coatings and Coverings
[0042] As described in detail above, fluid volume overload in the
vascular system of a patient, and in particular within the atria,
can cause an increase in atrial pressure. When exposed to elevated
atrial pressures, atrial tissue may be inclined to stretch over
time. Various mechanisms, coatings, coverings, devices, and
processes are disclosed herein for at least partially restraining
the left and/or right atrium from stretching to thereby reduce the
risk of post-operative atrial fibrillation. Atrial restraint
devices and methods disclosed herein may advantageously at least
partially restrict the expansion or stretching of atrial tissue,
while allowing for desirable expansion of the atria in order to
accommodate the proper contraction and expansion of the atria
typically associated with each heartbeat cycle. For example, that
diameter of an atrium may change by approximately 2 mm per beat for
a healthy heart. Therefore, in some implementations,
coatings/coverings and methods for restraining atrial stretch
according to the present disclosure may advantageously accommodate
approximately 2 mm per beat of diameter change of the atria, but at
least partially limit stretching beyond that.
[0043] As described above, the outward expansion of stretching of
the right and/or left atrium of the heart can result in development
of atrial fibrillation in some patients. For reference, FIGS. 3 and
4 show anterior and posterior views, respectively, of a heart 301
showing the surfaces of the right atrium 305 and the left atrium
302. Certain embodiments disclosed herein provide coatings and/or
coverings, and methods associated therewith, for restraining the
outward expansion of the atrial walls, which may be prone to
stretching and expansion due to increased fluid pressure therein,
which may be caused by fluid overload and/or other fluid management
conditions.
[0044] Stretching or expansion of the atria may be restrained
and/or prevented at least in part through the application of
external pressure on the outside surface of the atria. Some
embodiments disclosed herein relate to the placement of at least
partially rigid materials, structures, or forms on the surface of
the atria to thereby restrain expansion thereof. For example, in
some embodiments, atrial restraint is achieved through the
operative application of biocompatible adhesive coating onto the
atrial surface(s), which may serve to at least partially stiffen
the atrial tissue, thus preventing or limiting atrial stretching.
As described in detail above, the reduction of atrial stretching
may reduce the incidence of postoperative atrial fibrillation.
[0045] FIGS. 5 and 6 illustrates anterior and posterior views,
respectively, of a heart 501 having atrial restraint form or agent
530 applied to one or more atria thereof, to thereby restrain the
expansion and/or stretching of the atria. As shown, the right
atrium 505 and left atrium 502 have applied thereto a restraining
coating or covering 530. Although certain embodiments are disclosed
herein in the context of biocompatible adhesive coatings, it should
be understood that such embodiments may incorporate other types of
materials, such as patches, casts, and/or other forms comprising
any suitable or desirable at least partially rigid material, or
material that may become rigid through application of a certain
material, process, or treatment.
[0046] The application of, for example, a biocompatible adhesive
coating may at least partially prevent atrial stretching by way of
thickening of the atrial wall. Furthermore, atrial restraint
coatings and/or coverings as disclosed herein may further serve to
at least partially increase the atrial walls' modulus of
elasticity.
[0047] In some embodiments, the coating or covering 530 shown in
FIGS. 5 and 6 may comprise a bio-resorbable spray-on coating. Such
coating may have certain properties that may promote the restraint
characteristics of the coating and/or facilitate the application
thereof to the atrial wall. For example, the coating may comprise
hydrophobic polymer, which may be configured to adhere to the
atrial wall tissue. For example, such polymer may be doped with
carbon nanotubes (e.g., nanoscale pillars), and/or oxidized
dextran, which may provide improved adhesion characteristics.
[0048] In certain embodiments, the coating or covering 530 may
comprise light-cured adhesive material, which may become cured in
the presence of ultraviolet (UV), or other wavelengths of light. In
some embodiments, the covering or coating 530 comprises a
light-cured coating/adhesive that is configured to change color
when cured so as to inform the physician or technician of the
coverage areas of the cured adhesive. That is, the color of the
cured coating may provide a visual indication that the coating is
cured in a particular area. In light-cured adhesive embodiments,
the coating may be configured to cure within 20 minutes or less,
such as within a few minutes. The surface of the cured adhesive may
be such as to prevent adhesion of the treated atria to the chest
cavity. The atrial restraint material may advantageously have
relatively high-viscosity adhesive properties, which may be
preferable to promote and/or facilitate control of the application
of the material to the target area of the atrium or atria.
[0049] In some embodiments, the coating or covering 530 comprises
an at least partially flexible or elastic material, which may allow
for some degree of stretching to promote the proper contraction of
the atria in connection with heartbeat cycles. For example, the
coating or covering 530 may have a Young's modulus of elasticity
(E) between 0.2-1.0 MPa.
[0050] In some embodiments, the coating or covering 530 comprises
bio-resorbable material that is configured or designed to degrade
over a period of time after application thereof. For example, the
coating may degrade over a period of between 1 to 6 months, or over
period of time. The coating may comprise collagen, or the like.
[0051] With respect to embodiments in which the atria are
restrained using biocompatible adhesive material, such coating may
be applied in any suitable or desirable manner. For example, in
some embodiments, the coating material may be applied using a
brushed-on application, wherein a brush or similar type of tool or
device is utilized to apply and/or spread the material over the
surface of the atrium. In some implementations, the restraint
material may be sprayed onto the atrial surface, using some type of
spray application nozzle or tool. In some implementations, the
atrial restraint material may be applied using a sponge-on
application, wherein a sponge-type tool may be used to spread
and/or apply the material onto the atrial surface. In some
implementations, the atrial restraint material may be applied using
a syringe having an applicator tip, wherein restraint material may
be expelled from the applicator tip over the target area of the
atrium or atria. In some implementations, the atrial restraint
material (e.g. adhesive polymer) may be percutaneously injected via
a catheter to one or more additional treatment locations, such as
the left atrial appendage, cerebral aneurysm, or the like, and may
be cured via a light source that may be incorporated into the
delivery catheter.
[0052] In certain embodiments, the covering or coating 530 shown in
FIGS. 5 and 6 may comprise a tape or sheet form, which may be
pre-cut or cut in real-time to fit the desired target surface area
of the atrium or atria. That is, rather than applying an amorphous
coating to the atrial surface, embodiments disclosed here may
provide use of a shaped form of biocompatible material that may be
placed over the atrial surface. For example, one or more portions
of the covering 530 may comprise a patch that may be placed over
the target area. The patch may comprise any suitable material and
may advantageously have a suitable degree of rigidity to restrain
the stretching of the atrial tissue once the patch is placed and/or
secured. Such patch may comprise any suitable or desirable
material, such as mesh, cloth, or the like. Such a patch or
covering may be secured to the atria in any suitable or desirable
way, such as through suturing, or through the use of adhesives or
other attachment tool or mechanism. The covering 530 is configured
to at least partially restrain outward expansion of the surfaces of
the atria. With respect to embodiments of patch-type coverings 530,
such coverings may be secured to the surface of the atria using
adhesive. For example, the covering 530 may have adhesive
properties, and/or adhesive may be applied to the covering 530
and/or surface of the atria in order to adhere the covering 530 to
the atrial surface.
[0053] In some implementations, atrial restraint may be achieved
through the use of synthetic and/or memory metal (e.g. Nitinol)
mesh. For example, restraint mesh may comprise a restraint patch,
such as a Silastic patch. Such patch may be trimmed or customized
to fit a particular patient's atria or atrium. In some embodiments,
an atrial restraint patch may be sutured in place over the atrium.
Atrial restraint patches may advantageously comprise bio-resorbable
material, such that the patch need not be removed from the patient
after its useful life. In some embodiments, restraint is achieved
through the use of polymer film, which may be deposited or applied
to the regions of the atria that are desired to be restrained.
However, such films may not provide desirably uniform restraint
force in some implementations. Use of synthetic mesh may
advantageously provide desirable restraint, and may be formed to
fit a desired shape atria. Mesh restraint patches may be trimmed or
cut using scissors or other tools, such that a surgeon may be able
to fit or trim the patch him or herself at the time of an
operation. Furthermore, restraint patches in accordance with
embodiments of the present disclosure may comprise any suitable or
desirable material, including rigid or non-rigid cloths or forms.
Such patches/forms may be fixed to the atrial surface, or other
biological tissue or surface, in any suitable or desirable
manner
Additional Embodiments
[0054] Depending on the embodiment, certain acts, events, or
functions of any of the processes described herein can be performed
in a different sequence, may be added, merged, or left out
altogether. Thus, in certain embodiments, not all described acts or
events are necessary for the practice of the processes. Moreover,
in certain embodiments, acts or events may be performed
concurrently.
[0055] Conditional language used herein, such as, among others,
"can," "could," "might," "may," "e.g.," and the like, unless
specifically stated otherwise, or otherwise understood within the
context as used, is intended in its ordinary sense and is generally
intended to convey that certain embodiments include, while other
embodiments do not include, certain features, elements and/or
steps. Thus, such conditional language is not generally intended to
imply that features, elements and/or steps are in any way required
for one or more embodiments or that one or more embodiments
necessarily include logic for deciding, with or without author
input or prompting, whether these features, elements and/or steps
are included or are to be performed in any particular embodiment.
The terms "comprising," "including," "having," and the like are
synonymous, are used in their ordinary sense, and are used
inclusively, in an open-ended fashion, and do not exclude
additional elements, features, acts, operations, and so forth.
Also, the term "or" is used in its inclusive sense (and not in its
exclusive sense) so that when used, for example, to connect a list
of elements, the term "or" means one, some, or all of the elements
in the list. Conjunctive language such as the phrase "at least one
of X, Y and Z," unless specifically stated otherwise, is understood
with the context as used in general to convey that an item, term,
element, etc. may be either X, Y or Z. Thus, such conjunctive
language is not generally intended to imply that certain
embodiments require at least one of X, at least one of Y and at
least one of Z to each be present.
[0056] It should be appreciated that in the above description of
embodiments, various features are sometimes grouped together in a
single embodiment, figure, or description thereof for the purpose
of streamlining the disclosure and aiding in the understanding of
one or more of the various inventive aspects. This method of
disclosure, however, is not to be interpreted as reflecting an
intention that any claim require more features than are expressly
recited in that claim. Moreover, any components, features, or steps
illustrated and/or described in a particular embodiment herein can
be applied to or used with any other embodiment(s). Further, no
component, feature, step, or group of components, features, or
steps are necessary or indispensable for each embodiment. Thus, it
is intended that the scope of the inventions herein disclosed and
claimed below should not be limited by the particular embodiments
described above, but should be determined only by a fair reading of
the claims that follow.
* * * * *